2 Answers

You won't see anything particularly interesting. All the traffic is encrypted and only goes to gateway.discord.gg and some to discordapp.com. Traffic to other people in the Discord channel does not flow there directly so it's not possible to capture their traffic or see their IP addresses.

If you mean "can Wireshark dissect Discord traffic", it appears, from the reference for Discord, that it's built atop HTTP-over-TLS, so Wireshark should be able to dissect it, at least at that level. I don't think it knows how to, for example, dissect snowflakes. If Discord uses standard VoIP protocols for voice, it might be able to dissect that as well.

If you mean "does Wireshark support using Discord for chats from within Wireshark", the answer is "no"; Wireshark isn't an online multi-player game, so the lack of support shouldn't be surprising. :-)